The anabolic-androgenic steroids (AAS) are a family of hormones that includes testosterone and its synthetic derivatives. For decades, elite athletes have used AAS to improve performance, but it was not until the 1980s that illicit AAS use spread out of elite athletics and into the general population. Now, some 2 million Americans have used AAS, sometimes accumulating years of total exposure to highly supraphysiologic doses. Preliminary evidence suggests that long-term AAS use may cause serious medical consequences, including especially cardiovascular effects. However, these remain poorly understood, in part because until recently, most AAS users were still too young to have entered the age of risk. Now, this situation is poised to change, as the first large wave of illicit AAS users - those who first used AAS as youths in the 1980s - enters middle age. In a pilot study, now in press, our group used electrocardiography and echocardiography to compare 12 long- term AAS users, aged 32-46 years, and 7 age-matched weightlifters reporting similar exercise levels but no AAS use. Compared with nonusers, the AAS users showed significantly delayed myocardial depolarization, together with striking and highly significant impairments of cardiac contraction and relaxation (systolic and diastolic function), similar to those seen in established types of cardiomyopathy. Although we did not assess atherosclerotic disease in the pilot study, prior work by our group and others suggests that this too may be a consequence of AAS use. To further assess the effects of long-term AAS use, we propose to perform detailed medical and cardiac assessments in 80 long-term AAS users, 55 weightlifters reporting no history of AAS use, and 55 non-weightlifting men. Men will be recruited and screened using proven methods, developed by the PI over the last 10 years, designed to minimize selection and information bias to the maximum extent possible when studying illicit substance users. Our primary specific aim is to test the hypothesis that long-term AAS use causes 1) abnormalities of cardiac electrical conduction, characterized by delayed myocardial depolarization, increasing the risk for cardiac rhythm disturbances; 2) impaired myocardial function, characterized particularly by left ventricular diastolic and systolic dysfunction, increasing the risk for heart failure; and 3) accelerated atherogenesis, increasing the risk for myocardial infarction and other atherosclerotic disease. Our secondary specific aim is to assess other possible AAS effects by comparing the 3 groups using medical and laboratory tests focused especially on 1) the liver and kidney and 2) the hypothalamic-pituitary-gonadal axis. The medical effects of long-term AAS abuse are probably the least understood of any major form of drug abuse; no comparative study to date has performed full medical evaluations on a large group of chronic AAS users. This represents a serious deficit in scientific knowledge since, even by conservative estimates, hundreds of thousands of Americans have experienced long-term AAS exposure, and the older members of this group are just now reaching middle age. Thus the proposed study will have major public health impact.